Methods for manufacturing a tire mold and displacing the air from the mold into a compression cavity during the tire making process

ABSTRACT

A tire mold or a tire mold segment can include an air compression cavity, which connects to multiple surface connection slots having dimensions between 10 and 300 microns, which can be suitable for selective removal of air in the mold. The air compression cavity, can be close to the outside ambient, allowing the air escaping the interior of the mold to be compressed, which can assist in preventing the rubber material from leaving the mold pattern surface.

This application is a continuation of application Ser. No. 14/803,105,filed on Jul. 19, 2015, now abandoned, and a continuation of applicationSer. No. 14/556,222, filed on Nov. 30, 2014, now U.S. Pat. No. 9,085,114and claims priority from U.S. Provisional Application No. 62/006,864filed on Jun. 2, 2014 entitled “Methods for making a tire mold”, U.S.Provisional Application No. 62/032,526 filed on Aug. 2, 2014 entitled“Methods for making a tire mold”, and U.S. Provisional Application No.61/915,510 filed on Dec. 13, 2013 entitled “Methods and systems to keepa work piece surface free from liquid accumulation while performingliquid-jet guided laser based material processing” are which allincorporated herein by reference.

BACKGROUND

A tire mold usually consists of multiple tread segments that togetherform a full circular tread mold. The mold is closed on the side by aside ring, which typically has the tire brand engraving, and otherinformation such as size and operating pressure. The tire mold treadsegment surface is shaped to be the negative of the actual tire treadsurface. The tire tread mold segments and the 2 side rings, are heldtogether by a container.

The tire mold segments can include vent structures to selectivelyevacuate air from the tire mold. Various methods for air evacuation havebeen described, with high manufacturing complexity and maintenanceefforts such as cleaning or replacement.

U.S. Pat. No. 4,812,281 discloses vent holes, having a diameter between3.81 to 12.7 mm, to allow air to be evacuated through such holes thatfluidly connect the mold inner surface to the mold outer surface.

U.S. Pat. No. 6,923,629 describes spring vents, which can close the ventstructure once the tire green has complete filled up the tread patternin the mold. During the rubber vulcanization process, air can escapethrough the vent holes, with the spring loaded pins stopping the rubbermaterial from entering the vent holes. Spring vents can be costly, forexample, can contribute up to 10% of the manufacturing cost of the mold.

U.S. Pat. Nos. 6,382,943 and 6,826,819 describe a ventless approach inwhich the tread pattern surface of the mold is built up by many smallpitches, also referred to as puzzle elements. Air is evacuated byleaving a small gap between such puzzle elements. The gap is chosen insuch way that the air can pass through while at the same time the rubberis held back during the curing process. The ventless process can belimited to simple tread pattern. For example, winter tires can have atoo complex tread pattern to be built as a puzzle. Further, puzzle moldcan incur high manufacturing cost, which can be up to twice as expensiveas a regular segmented mold.

Patents EP2719524 and DE102012104500 describes micro-venting channels,which connect the tread mold surface to an evacuation cavity such as ahole on the rear side of the mold. The channels are narrow enough tohold back the rubber during the curing process, while at the same time,allowing air to be evacuated. As each slot can require a connection to aventing cavity, several thousand of such evacuation cavities can berequired for venting of a complex tread pattern.

U.S. Pat. No. 8,834,143 describes mechanical inserts to create narrowslots for air venting. This can result in several thousand inserts for acomplex tread design such as for a winter tire. Tight tolerance of boththe slots and the inserts can be required, for example, to avoidejection upon de-molding of the cured tire.

Thus there is a need for improved systems and methods for curing tires.

SUMMARY OF THE DESCRIPTION

In some embodiments, the present invention discloses tire cure moldsegments having air compression cavities. Surface connection slots canconnect the air compression cavities with the tread surface of the tiremold segments. During a curing process, air can be displaced from themold into the air compression cavity, for example, through the surfaceconnection slots, to allow the rubber to adopt exactly the shape of themold surface topography, and thus result in a proper tire surfaceprofile for the cured tire. The tire molds, and the methods for makingthe tire mold as described in this invention can reduce the amount ofmanufacturing steps that are required for making a reliable airevacuation operation.

The air compression cavity can be isolated from the external ambient,thus air in the air compression cavity can be compressed during thecuring process. For example, at the beginning of the curing process, thepressure in the air compression cavity can be at atmospheric pressure.During the tire curing process, air is displaced from the mold into theair compression cavity, increasing the pressure. The increased pressurecan assist in blocking the rubber material from entering the surfaceconnection slots, resulting in desired tire surface profiles.

The air compression cavity can be coupled to an external equipment, suchas a vacuum system or a source of pressurized fluid and/or gas. Thevacuum system can assist in displacing air from the mold into acompression cavity. The pressurized fluid can assist in removing thecured tire from the mold, or in cleaning the mold.

In some embodiments, the present invention discloses methods for forminga tire mold, including a tire mold segment. Air compression cavities canbe formed in the tire mold body. Sipe slots and surface connection slotscan be formed, for example, by a liquid jet guided laser system. Apressurized fluid, such as alcohol, alcohol aerosol, and/or air, can beapplied to the air compression cavities to clean the tire mold.

In some embodiments, the present invention discloses methods for formingtires from tire mold segments having air compression cavities. Multipletire mold segments can be assembled to form a circumferential moldcovering a green tire. The green tire can be cured, and during thecuring process, air in the tire mold can be displaced to the aircompression cavities. After the curing process, a compressed source,such as a compressed air, can be applied to the air compressioncavities. The compressed air can enter the surface connection slots,forming a layer of air at an interface between the cured tire and themold. The air layer can reduce the adhesion between the cured tire andthe mold, which can facilitate the removal of the cured tire from themold. The tire mold segments can be disassembled, and the cured tire isremoved from the disassembled mold. Coupling elements can be placedbetween the tire mold segments for connecting the air compressioncavities between the tire mold segments. A pressure source, such as apressurized fluid, can be applied to the air compression cavities. Thepressurized fluid can enter the surface connection slots, removingrubber debris from the air connection slots. The coupling elements canbe removed, and the tire mold segments is ready for processing anothergreen tire.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1B illustrate tire molds having tire segments according to someembodiments.

FIGS. 2A-2C illustrate an air compression cavity in a tire mold segmentaccording to some embodiments.

FIG. 3 illustrates a flow chart for forming a tire mold segmentaccording to some embodiments.

FIGS. 4A-4B illustrate air compression cavities from hollow conduitsaccording to some embodiments.

FIGS. 5A-5B illustrate operating configurations for an air compressioncavity according to some embodiments.

FIGS. 6A-6C illustrate a configuration for multiple surface connectionslots intersecting an air compression cavity according to someembodiments.

FIGS. 7A-7B illustrate a tire mold segment and a complete tire moldhaving an air compression cavity according to some embodiments.

FIGS. 8A-8E illustrate a tire mold segment having air compressioncavities according to some embodiments.

FIGS. 9A-9B illustrate a tire mold segment having an air compressioncavity according to some embodiments.

FIGS. 10A-10C illustrate a tire mold segment having sipes with a conduitpassage according to some embodiments.

FIGS. 11A-11D illustrate configurations for tire mold segments having anair compression cavity according to some embodiments.

FIGS. 12A-12C illustrate configurations for tire mold segments having anair compression cavity according to some embodiments.

FIGS. 13A-13B illustrate complete tire mold configurations according tosome embodiments.

FIG. 14 illustrates a flow chart for forming a tire mold or a tire moldsegment according to some embodiments.

FIGS. 15A-15E illustrate a process for forming a tire mold segmentaccording to some embodiments.

FIGS. 16A-16C illustrate a process for forming a tire mold segmentaccording to some embodiments.

FIG. 17 illustrates a flow chart for forming a tire mold or a tire moldsegment having an air compression cavity according to some embodiments.

FIGS. 18A-18F illustrate configurations for forming an air compressioncavity according to some embodiments.

FIGS. 19A-19D illustrate a process for forming an air compression cavityaccording to some embodiments.

FIG. 20 illustrates a flow chart for forming a tire mold or a tire moldsegment according to some embodiments.

FIGS. 21A-21C illustrate a two-part tire mold segment according to someembodiments.

FIGS. 22A-22B illustrate different configurations for two part moldsaccording to some embodiments.

FIG. 23 illustrates a flow chart for forming a tire mold according tosome embodiments.

FIG. 24 illustrates a liquid jet guided laser system according to someembodiments.

FIGS. 25A-25B illustrate configurations of surface connection slot usinga liquid jet guided laser process according to some embodiments.

FIGS. 26A-26C illustrate configurations for air compression cavitiesaccording to some embodiments.

FIGS. 27A-27C illustrate an end point detection for a surface connectionslot formation according to some embodiments.

FIG. 28 illustrates a flow chart for a tire mold formation processaccording to some embodiments.

FIGS. 29A-29C illustrate a process for cleaning a tire mold segmentafter formation according to some embodiments.

FIG. 30 illustrates a flow chart for cleaning a tire mold after makingthe tire mold according to some embodiments.

FIGS. 31A-31C illustrate processes for cleaning a tire mold segmentaccording to some embodiments.

FIGS. 32A-32D illustrate a process for post treatment a tire moldaccording to some embodiments.

FIG. 33 illustrates a flow chart for cleaning a tire mold according tosome embodiments.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In some embodiments, the present invention discloses methods and systemsfor making molds, such as tire mold segments or complete tire molds,which can include multiple tire mold segments assembling together. Thetire molds can include one or more air compression cavities, with eachair compression cavity connected to multiple surface connection slotsfor accepting air from the mold to be compressed in the air compressioncavity. The surface connection slots can have a dimension allowing airto pass through, but blocking rubber materials. Alternatively, or inaddition, the volume of the air compression cavities can be selected togenerate an air pressure in the air compression cavities, which canassist in blocking the rubber materials from entering the surfaceconnection slots.

In some embodiments, the present invention discloses tire molds, whichinclude surface connection slots leading to air compression cavities inthe tire molds, and methods to form tire molds. The surface connectionslots and sipe slots in the tire molds can be created using a liquid jetguided laser system.

In some embodiments, the present invention discloses a tire curing moldsegment, and operations related to the tire curing mold segments, suchas fabricating the tire mold segments, operating the tire mold segmentsin a tire curing process, and cleaning the tire mold segments. Air canbe displaced from the mold into a cavity, e.g., called an aircompression cavity since air is led to and then being compressed in thecavity, during the curing process to allow the rubber to adopt exactlythe shape of the mold surface topography and thus result in a propertire surface profile for the cured tire. The present method for making atire mold can reduce the amount of manufacturing steps that are requiredfor making a reliable air evacuation operation.

The present air compression cavity can be distinct and have advantagesover prior arts of removing air to the outside ambient. For example, ascompared to micro-holes, for example, described in U.S. Pat. No.4,812,281, the number of air compression cavities can be significantlyless, e.g., can be between 4 and 20, as compared to up to 8,000 holes inthe micro-hole process, leading to less manufacturing complexity andmaintenance efforts. As compared to sprint vents, for example, describedin U.S. Pat. No. 6,923,629, the air compression cavity process canpresent less complexity and lower cost due to the avoidance of thespring vent elements, and less maintenance efforts due to the cleaningand replacement of the spring vent elements. As compared to ventlesstechnology, for example, described in U.S. Pat. Nos. 6,382,943 and6,826,819, the air compression cavity process can present lesscomplexity and lower cost due to enabling the use of large moldsegments, instead of up to more than 100 puzzle mold pieces. As comparedto micro-venting channels, for example, described in patentsEP2719524A1, and DE102012104500A1, the number of air compression cavitycan be significantly less, as compared to several thousand of evacuationcavities on the rear side of the mold. As compared to mechanical insertprocess, for example, described in U.S. Pat. No. 8,834,143, the surfaceconnection slots can present less complexity and lower cost since itdoes not require a large amount of mechanical inserts with accuratepress fit insert.

In some embodiments, the present invention discloses methods for makinga tire mold that can allow air to enter into a surface connection slotduring the tire curing process, with the surface connection slot beingnarrow enough to limit the rubber from entering into such slot. Thesurface connection slots can be connected to few but large aircompression cavities inside the mold segment. The surface connectionslots can be generated by means of a single mechanical processing stepimmediately in the required width, thus making the use of any insertsobsolete. The large air compression cavities in the mold can be used tocompress or pressurize the air instead of evacuating or venting the airwith the purpose of further limiting the rubber to enter into thesurface connection slots that connect to the mold surface. The large aircompression cavities in the mold can be used to connect to a highpressure liquid or gas source (e.g., air) to allow cleaning of the moldin regular intervals (rubber debris removal from the surface connectionslots). The large air compression cavities in the mold can be used tocreate process control by accepting sensors for the manufacturingprocess of the connecting surface connection slots.

In some embodiments, the present invention describes a cost-effectiveproduction of the mold, secures a robust mold architecture byeliminating the need of any mechanical or inserted and post-fixed partsfor air evacuation, and facilitates a simple cleaning process for theair evacuation structures.

Tire molds are typically made from metal or metal alloy materials, suchas aluminum or steel, which can be cast or CNC machined to form thedesired negative tread pattern. Tire mold tread layers can also be madefrom an additive manufacturing technology, such as 3D printing, whichare then coupled to tire mold supports.

FIGS. 1A-1B illustrate tire molds having tire segments according to someembodiments. In FIG. 1A, a tire mold can include multiple moldcomponents 100 assembled together, including a tire mold segment 110 andside rings 190. The tire mold segment 110 can include tread patternblocks 150 for forming tread blocks in a tire, including sipes 130 andtread block sidewalls 155. In FIG. 1B, a complete tire mold 105 caninclude multiple tire mold segments 110 assembled together to form acomplete circumferential mold, with the air compression cavities 140from different tire mold segments connected to each other to form largerair compression cavities. As shown, the air compression cavity 140 isdisposed along a circumferential direction 180 of the tire or the tiremold 105. Other configurations can also be used, such as the aircompression cavity is disposed along a width direction 185 across athickness of the tire or the tire mold 100.

Each air compression cavity is isolated from nearby air compressioncavities, or each two air compression cavities are coupled to eachother.

In some embodiments, the tire mold segment 110 can be made from amaterial having high anti-sticking coefficient. Thus the rubber tire 160can be easily removed from the tire mold after completing thevulcanization process. The tire mold segment can have surface connectionslots 120, which are small enough for air to pass through withoutallowing the rubber material to enter. For example, the surfaceconnection slots 120 can include a line having a line width 125, whichcan be between 10 and 300 microns. The surface connection slots can beformed by a cutting process, such as a liquid jet guided laser cutting.

In some embodiments, the tire mold segment 110 can have air compressioncavities 140 embedded inside the tire mold. The cavities can store theair in the mold, e.g., can provide a location to displace the air into,for example during the tire curing process. The evacuation of the airinside the mold can prevent the air to be trapped in the mold, which canresult in the formation of irregularities in the cured tire surface thatcan have the shape of the respective air bubbles in the tires. The airinside the mold, after being evacuated, can be directed to the cavitiesin the form of compressed air. The compressed air can be configured,e.g., the air compression cavities 140 can be designed to have a properdimension 145, to exert a slight pressure, such as between 1 and 2 bars,to ensure that the rubber material completely fills the tire moldinterior, but preventing the rubber material from entering the surfaceconnection slots. For example, the cavities can have a cylindricalshape, with a diameter in order of millimeters, such as between 1 and 10mm, or between 3 and 5 mm. The cavities can have other shapes, such asrectangles or lines running along or intersecting the surface connectionslots.

In some embodiments, the present invention discloses a tire mold thatincludes multiple mold segments and supports, including mold inserts forforming tire treads. Some mold segments can have a tread pattern that isused to form treads in a rubber tire. Some mold supports can have aground surface without tread pattern that is used to mount mold insertswith tread pattern.

In some embodiments, the present invention discloses methods and systemsto form a tire mold or a tire mold segment using an air compressioncavity. Instead of exhausting the air in the tire mold to the outsideambient during the vulcanization process, the air can be compressed intoa cavity. The air compression cavity can accept the air from the tiremold, thus functioning as an exhaust for the air inside the tire mold.Further, different from ambient air exhaust, the air compression cavitycan have pressure built up in the cavity, which can assist in blockingrubber material from protruding outside the tread surface. For example,at a beginning of a tire vulcanization process, the pressure in the aircompression cavity is at atmospheric pressure. When the rubberapproaches the surface connection slots, air can escape to the aircompression cavity, increasing the pressure in the cavity. The increasedpressure can stop the rubber material from entering the cavity.

In some embodiments, the air compression cavity is embedded inside thetire mold segment, without any access, e.g., fluid communication, to theoutside ambient, e.g., there is no connection from the air compressioncavity to the outside surface of the tire mold segment. The aircompression cavity can have multiple connections, e.g., connectionsthrough the air compression cavity to the tread surface of the moldsegment. The connections can have a dimension less than the volumedimension of the cavity, such as a dimension calculated to allow air toenter the cavity but not rubber material. The air compression cavity canhave a large volume, such as a volume calculated to contain the airinside the tire mold portion in pressurized form.

A tire mold can consist of multiple mold segments. Each mold segment canhave a tread surface. This tread surface is the negative shape of thetire. The mold segments can be closed to form one circumferentiallyclosed mold in which a tire can be cured.

For curing, the tire is inserted into the mold and the mold segments areclosed as described above. Upon closure of the mold, the rubber of thetire green is pressed into the negative tread pattern. The tire greenmust exactly adopt the shape of the tread pattern in the mold. To allowthis, the air layer between the tire green and the mold must bedisplaced into a suitable and big enough cavity.

In some embodiments, the present invention discloses using large aircompression cavities to displace the air into during the curing process.The large compression cavities can be placed in a circumferentialdirection 180 inside the mold segment. The amount of compressioncavities can match the amount of tread blocks in lateral direction ofthe profile i.e. in case of 3 circumferential tread grooves there can beonly 4 compression cavities needed. The large compression cavities canbe placed in a cross direction 185 making an angle, such as 90° to thecircumferential direction 180. The number of cavities can be higher toconnect all the tread pattern. Other angles can be used. In addition, acombination of cavities having the circumferential direction and thecross directions, which can be cross-linked.

The compression cavities are fluidly connected to the mold tread surfaceby surface connection slots. These surface connection slots can be 10 to300 um to allow air passing through, but to limit rubber from enteringinto the slots. The direction of the slots in the tread profile can bein any direction. To connect as much of the tread block to thecompression cavity it can be preferential to position the slots in thesame direction as the sipes i.e. in between the sipes. The slots canfollow any freeform shape such as a line, a sine, a wave etc.

To create an effective volume flow into the compression cavity, theslots can be 0.3-6 mm deep, e.g., the compression cavity is located0.2-5.5 mm below the tread surface of the mold.

After the tire is cured, the mold is opened again. An active flow of aircan be provided to the compression cavity using a one-way valve to buildan air-layer between the mold and the cured tire to facility thede-molding. A suitable pressure can be selected to improve this effect,for example 1-2 bar.

After the tire is de-molded, a higher pressure can be used to remove anydebris from the slots, for example 4-10 bar.

FIGS. 2A-2C illustrate an air compression cavity in a tire mold segmentaccording to some embodiments. The tire mold segment can have a negativesurface profile of the tire tread pattern on an inner surface, which canallow the transfer of the tire tread pattern to the rubber tire. The airin the tire mold can be evacuated to an air compression cavity,preventing the air to form bubbles or other defects during the formationof the tire. The tire mold can include air evacuation structures, e.g.,slits in the mold, having dimensions between 10-300 microns, to allowair to escape but blocking rubber material.

A tire mold segment 210 can include a negative image of a tread pattern.The tread pattern can include multiple tread blocks 250, which areseparated from each other by tread block sidewalls 255. In the treadblock 250 and inside the tire mold segment body, an air compressioncavity 240 can be included, together with a surface connection slot 220at an opening of the cavity. The air compression cavity 240 is isolatedfrom an outside ambient. Other components can be included, such assipes.

Rubber material 260 can approach the tread pattern of the tire moldsegment 210. Air inside the tire mold segment can enter 270, e.g.,through the surface connection slot 220, to the air compression cavity240. The pressure 240A in the air compression cavity 240 can graduallyincrease.

As the rubber material approaching the tread pattern, more air can enter272 the air compression cavity, increasing the pressure 240B in thecavity 240. The rubber material can stop at the surface connection slot220, for example, due to the dimension of the surface connection slot220, that is large enough to allow air to pass through, but is smallenough the prevent the passage of the rubber material. The pressure 240Ccan be constant after the rubber material reaches the surface connectionslot 220. The pressure 240C in the air compression cavity 240 can belarge enough to exert a force 286 on the rubber material at the surfaceconnection slot 220. Thus the air compression cavity can assist instopping the rubber material from entering the surface connection slot.

The cavity can start from the opposite side of the mold, e.g., the outersurface of the mold or the surface not having the tread pattern. Thecavity can have different sizes and shapes, such as cylindrical shape orrectangular shape, cone shape, or flat cone shape, e.g., cone shape withflat top.

The surface connection slots can include multiple surface connectionslots, either straight lines or curve lines. For example, more than onesurface connection slot can be used for large tread blocks, e.g., toallow complete evacuation of air in the tread block during thevulcanization process.

In some embodiments, a liquid jet guided laser system (such as describedin for example U.S. Pat. No. 8,859,988, which is hereby incorporated byreference in its entirety for all purpose) can be used to form thesurface connection slots 220, having practically any patterns. An x-ymechanism, such as a CNC mechanism, with ultimately 5 axis movement) canbe coupled to the liquid guided laser beam, which can move the laserbeam in any directions to form the patterns. Thus the surface connectionslots can include multiple channel lines, either straight lines or curvelines, depending on the requirements of the object. For example, fortire molds, more than one surface connection slot can be used for largetread blocks, e.g., to allow complete evacuation of air in the treadblock during the vulcanization process.

FIG. 3 illustrates a flow chart for forming a tire mold segmentaccording to some embodiments. Operation 300 provides a tire mold body.The tire mold body can include a tire mold segment. The tire mold bodycan have a tread pattern formed on an inner surface, e.g., a treadsurface of the tire mold body. The tire mold body can be cast, milled,or built, for example, by an additive manufacturing process. The tiremold can also have sipes installed, for example, in tread blocks of thetread pattern. The tire mold body can be in one piece, or can be inmultiple pieces that can be attached together. Operation 310 forms atleast an air compression cavity inside the tire mold body. In someembodiments, the air compression cavity can be formed at an outersurface of the tire mold body, and then a cover can be placed to blockor seal the opening to the air compression cavity. Alternatively, avalve can be coupled to the opening to the air compression cavity, toprovide controlled access to the air compression cavity. Operation 320forms more than one surface connection slots from a surface of the tiremold body, such as the tread pattern surface. The surface connectionslots can be connected to the air compression cavity. Multiple surfaceconnection slots can be formed connected to an air compression cavity,thus can simplify the fabrication process of the tire mold segment. Thenumber of the surface connection slots can be determined by the types ofthe tires, for example, high performance or winter tires can have moresurface connection slots due to the complexity of the tread pattern.Using multiple surface connection slots to connect to an air compressioncavity, a much reduced number of air compression cavities can be used.For example, 4-10 air compression cavities can be formed for a tire moldsegment, as compared to thousands of blind holes at the backside of eachsurface connection slot to outside atmosphere.

In some embodiments, the volume of the air compression cavity can beconfigured to prevent a rubber material from entering the surfaceconnection slots due to increased pressure caused by air compression320.

Different air compression cavity configurations can be used, togetherwith different methods of forming the air compression cavity. The aircompression cavity can be characterized as a volume that can beconnected to more than one, such as 10, 20, 60, or even 100 surfaceconnection slots. The air compression cavity can be completely isolated,e.g., sealed, from the outside ambient, e.g., as a closed cavity insidethe tire mold segment. The air compression cavity can be conditionallyisolated, for example, the air compression cavity in a tire mold segmentcan be open to outside ambient, but the openings can be coupled to anearby tire mold segment, so that the composite cavity can be isolatedfrom the ambient. The air compression cavity can be connected to a valveleading to an external equipment. Thus by closing the valve, the aircompression cavity is isolated from the ambient, and by opening thevalve, the air compression cavity can be connected to the externalequipment, such as a vacuum pump assembly for faster and more efficientdisplacement of air from the mold into a compression cavity, or a sourceof a compressed gas, liquid, or gas/liquid mixture for pressurizing orfor cleaning the cavity and the surface connection slots. The valve canbe an one-way valve, which, in some cases, can allow compressed gas,liquid, or gas/liquid mixture to enter the cavity to clean the tiremold, while functioning as a closed cavity.

In some embodiments, the air compression cavity can be coupled to anoutlet, which can be sealed to form a close cavity, or can be coupled toa compressed source for cleaning the surface connection slots, or can becoupled to a vacuum system to assist in displacement of air from themold into a compression cavity, or can be coupled to a compressed gassource to apply pressure to facilitate the de-molding process.

Different configurations of the air compression cavity can be used. Forexample, the air compression cavity can be simply a cavity inside thetire mold segment. The air compression cavity can include a hollowconduit, such as a hollow round tube, a hollow square tube, or a hollowtube having any shape.

FIGS. 4A-4B illustrate air compression cavities from hollow conduitsaccording to some embodiments. In FIG. 4A, a cavity 440 can be formed ina tire mold segment 410 using a hollow element 441. For example, ahollow round tube (or other hollow elements) can be placed in a moldduring the casting process to form the tire mold. After the mold isformed with the hollow tube embedded in the tire mold, surfaceconnection slots 420 can be formed, for example, by a liquid jet guidedlaser system 470 (such as described in for example U.S. Pat. No.8,859,988), cutting through the tire mold material and the shell of thehollow tube to connect to the inner volume of the hollow tube. Otherconfigurations can be used. For example, FIG. 4B shows a cavity 442formed by using a square hollow tube 443.

FIGS. 5A-5B illustrate operating configurations for an air compressioncavity according to some embodiments. In FIG. 5A, a tire mold segment510 can have an air compression cavity 540 embedded in the tire moldsegment 510. The air compression cavity 540 can have an outlet 542connected to an outside ambient. A valve assembly 570 can be coupled tothe outlet 542, for example, to have access to the air compressioncavity 540. A vacuum system 577 can be coupled to the valve assembly570, for example, to assist in displacement of air from the mold segmentinto a compression cavity. Another system 575, such as a pressurizedfluid or a compressor assembly, can also be coupled to the valveassembly 570, for example, to provide a fluid, such as a gas, a liquid,or a mixture of gas and liquid, to the air compression cavity 540.

FIG. 5B shows pressure curves as a function of time for differentoperating configurations of the tire mold. The valve assembly 570 can beclosed at all time. The air compression cavity 540 can be at anatmospheric air pressure. During the tire making process, air inside thetire mold can be evacuated from the tire mold and stored in the aircompression cavity 540, increasing the air pressure 580 of the aircompression cavity 540. When the rubber material is completely filledthe tire mold, the air pressure 590 in the air compression cavity canbecome constant, e.g., all the air in the tire mold has been stored inthe air compression cavity. The volume of the air compression cavity canbe configured so that the air pressure 590 can assist in blocking therubber material from entering the surface connection slots.

In some embodiments, the valve assembly 570 can be open to thecompressor assembly 575. For example, the compressor assembly 575 canincrease the pressure 581 in the air compression cavity to be above theatmospheric air pressure. The pressure increase can be small, to allowthe air in the tire mold to be evacuated to the air compression cavity.The compressor can increase the final pressure 591 of the aircompression cavity, for example, to better assist in blocking the rubbermaterial from entering the surface connection slots. The compressor canprovide different additional air pressure at different time, forexample, to increase the initial pressure 581 to be above atmosphericpressure, and to not increase the final pressure 590 to be the same aswithout operating the compressor. Alternatively, the compressor can beoff at the beginning, to provide an initial pressure 580 at atmospheric.The compressor can start, to bring the final pressure 591 to be abovethe pressure 590. Other configurations can also be used, changing theoperation of the compressor to assist in evacuating the air in the tiremold, and to preventing the rubber material from entering the surfaceconnection slots.

In some embodiments, the valve assembly 570 can be open to the vacuumassembly 577. For example, the vacuum assembly 577 can lower thepressure 582 in the air compression cavity to be below the atmosphericair pressure. The low pressure level can allow the air in the tire moldto be displaced easier to the air compression cavity. The vacuumassembly can lower the final pressure 592 of the air compression cavity.The vacuum assembly can provide different air pressure at differenttime, for example, to lower the initial pressure 582 to be belowatmospheric pressure, and to not increase the final pressure 590 to bethe same as without operating the compressor. Alternatively, the vacuumassembly can be off at the beginning, to provide an initial pressure 580at atmospheric. The vacuum assembly can start, to bring the finalpressure 592 to be below the pressure 590. Other configurations can alsobe used, changing the operation of the vacuum assembly to assist indisplacement of air from the mold into a compression cavity.

In some embodiments, a combination of the compressor 575 and the vacuumassembly 577 can be used. For example, the vacuum assembly can start ata beginning of the tire making process, lowering the pressure 582 in theair compressor cavity to be below atmospheric pressure, to assist indisplacement of air from the mold into a compression cavity. Thecompressor can start at an end of the tire making process, increasingthe pressure 591 in the air compressor cavity to be at an appropriatepressure, to assist in blocking the rubber material from entering thesurface connection slots, and to possibly facilitate the tire de-moldingprocess.

FIGS. 6A-6C illustrate a configuration for multiple surface connectionslots intersecting an air compression cavity according to someembodiments. A tire mold segment 610 can have an air compression cavity640, which can be formed by a hollow tube 641 embedded in the tire moldsegment 610. The tire mold segment 610 can have a tread pattern surface,which can include multiple tread blocks 650 separated by tread blockside walls 655.

FIG. 6A shows a perspective view of the air compression cavity 640 andthe surface connection slots 620. The tire mold segment and the treadpattern are omitted in this figure to show the relationship between theair compression cavity 640 and the surface connection slots 620. FIG. 6Bshows a cross section view A-A′, cutting along a length of a surfaceconnection slot 620. FIG. 6C shows another cross section view B-B′,cutting along a length of the air compression cavity 640. The aircompression cavity 640 can be placed at an angle with the surfaceconnection slots 620, e.g., the air compression cavity 640 and thesurface connection slots 620 are not substantially parallel, so thatmultiple surface connection slots 620 can intersect the air compressioncavity 640 with a short separation.

FIGS. 7A-7B illustrate a tire mold segment and a complete tire moldhaving an air compression cavity according to some embodiments. In FIG.7A, a tire mold segment 710 can include multiple air compressioncavities 740 passing through the tire mold segment 710. The aircompression cavities can be configured to be under the tread surface ofthe tire mold segment, and can be configured to cross multiple treadblocks 750 of the tire mold segment. The air compression cavities can beconfigured to intersect multiple surface connection slots 720, which areformed in cavities formed between sipes 730 and tread block side walls755. As shown, the air compression cavities 740 are disposed along acircumferential direction 780 of the tire 700. Other configurations canbe used, such as disposing the air compression cavities along a widthdirection 785, e.g., across a thickness or a width of the tire mold.Other directions can also be used.

In FIG. 7B, multiple tire mold segments 710 can be assembled to form acomplete tire mold 700. The air compression cavities 740 can beconnected between the tire mold segments to form close air compressioncavities for the complete tire mold.

FIGS. 8A-8E illustrate a tire mold segment having air compressioncavities according to some embodiments. FIG. 8A shows a top view, andFIG. 8B shows a cross section C-C′ of a tread block 850. A tire moldsegment 810 can include a tread pattern, which include multiple treadblocks 850, separated by tread block sidewalls 855. Air compressioncavities 840 can run across and under the tire mold segment. Thedirection of the air compression cavities can be designed to intersectmultiple surface connection slots 820. For example, the air compressioncavities 840 can run along a circumferential direction 880 of the tiremold.

In the tread block 850, sipes 830 can run across the tread block 850,separating the tread block into multiple areas. Each area thus will needa surface connection slot 820, in order to remove the air to preventdefects in the rubber tire during the curing process. Each surfaceconnection slot 820 can intersect the air compression cavity 840, sothat the air can enter the air compression cavity 840. With the aircompression cavity running across multiple tread blocks and forming anangle with the area that the air needs to be removed, the surfaceconnection slots 820 can be cut anywhere in the tread block, and stillintersecting the cavity 840.

FIGS. 8C-8E show different configurations of the air compressioncavities. FIG. 8C shows a tire mold segment 811 having air compressioncavities 841 forming an angle with the circumferential direction 880 orwith the thickness (or width) direction 885. FIG. 8D shows a tire moldsegment 812 having air compression cavities 842 running across thethickness (or width) direction 885. FIG. 8E shows a tire mold segment813 having air compression cavities 843/844 forming a net under thetread pattern of the tire mold segment, including air compressioncavities 843 running along the circumferential direction 880 and aircompression cavities 844 running across the thickness (or width)direction 885. Other configurations can be used.

In some embodiments, the air compression cavity 840 can have structuralsupports, for example, to increase structural integrity of the tire moldsegment. The structural supports can be configured to allow air to passthrough, for example, having conduit passages in the structuralsupports. Other configurations can be used, such as a metal wall hollowelement, in which the metal wall can serve as structural support for theair compression cavity on the tire mold segment.

In some embodiments, surface connection slots can be used together withair compression cavities. In certain areas, conventional ventingtechnology can be used, such as air evacuation cavity process, in whichthe air is evacuated to the outside ambient. In certain areas, aircompression cavity process can be used, which can potentially save up to8000 backside drilled holes in each tire mold.

In some embodiments, the air compression cavity can be connected to thetread walls of the tread blocks in a tire mold segment. A surfaceconnection slot can be used to connect the tread walls to an aircompression cavity.

FIGS. 9A-9B illustrate a tire mold segment having an air compressioncavity according to some embodiments. A tire mold segment 910 caninclude multiple air compression cavities passing through the tire moldsegment 910. For example, an air compression cavity 940 can beconfigured to be connected to surface connection slots 920 forevacuating air in recesses between sipes 930 and tread walls 955. An aircompression cavity 945 can be configured to be connected to surfaceconnection slots 925 coupled to tread walls 955. An air compressioncavity 947 can be configured to be connected to both surface connectionslots 920 and surface connection slots 925.

In some embodiments, the present invention discloses systems and methodsto improve the reliability of the tire mold process. A surfaceconnection slot dimension can be small, such as between 10 to 300microns, thus can be clogged, for example, due to the rubber residues inthe vulcanization process. The sipes can have conduit passages, e.g.,sipes having holes or lines, so that air can pass from one side of thesipes to the other side. Thus, if a surface connection slot is clogged,air can pass through the conduit passages of the sipes to enter thenearby surface connection slots.

FIGS. 10A-10C illustrate a tire mold segment having sipes with a conduitpassage according to some embodiments. FIGS. 10A-10B shows a crosssection view and a perspective view of a tread block 1050 having sipes1030 with conduit passage 1032. The areas defined by the sipes and thetread block sidewall 1055 all can have surface connection slots 1020connecting to an air compression cavity 1040. As shown, the conduitpassage 1032 has a shape of a slot which can be preferred to let airpass through but to prevent the rubber from entering the conduit. Otherconfigurations can also be used, such as circular holes or elongatedholes. In addition, the conduit passage 1032 can be placed close to thetread surface, such as less than 2 mm, or less than 1 mm from the treadsurface.

FIG. 10C shows an operation of the air passage if there is a clog in asurface connection slot 1025. Air in area 1072 can pass through theconduit passages 1032A and 1032B to nearby surface connection slots1025A and 1025B, respectively. For example, an air flow 1074 can startin area 1072, and pass through conduit passage 1032A to a nearby area1072A to be removed through the nearby surface connection slot 1025A.

FIGS. 11A-11D illustrate configurations for tire mold segments having anair compression cavity according to some embodiments. In FIG. 11A, atire mold segment 1110 can have an air compression cavity 1140 havingopen ends 1170 and 1180. The air compression cavity can be embedded inthe body of the tire mold segment 1110. The tire mold segment 1110 caninclude multiple tread blocks 1150, together with sipes 1130 and surfaceconnection slots 1120 for leading air to the air compression cavity1140. In FIG. 11B, a tire mold segment 1111 can have an air compressioncavity 1141 having open ends 1171 and 1181. The open ends 1171 and 1181can have optional mating elements, for example to couple with aircompression cavities of nearby tire mold segments.

In FIG. 11C, a tire mold segment 1112 can have an air compression cavity1142 having an open end 1172 and a close end 1182. The open end 1172 canhave a mating element, for example, to couple with another aircompression cavity of a nearby tire mold segment. In FIG. 11D, a tiremold segment 1113 can have an air compression cavity 1143 having closeends 1173 and 1183.

FIGS. 12A-12C illustrate configurations for tire mold segments having anair compression cavity according to some embodiments. In FIG. 12A, atire mold segment 1210 can have an air compression cavity 1240 havingopen ends 1270 and 1280. The air compression cavity can be embedded inthe body of the tire mold segment 1210. The tire mold segment 1210 caninclude multiple tread blocks 1250, together with sipes 1230 and surfaceconnection slots 1220 for leading air to the air compression cavity1240. The air compression cavity 1240 can also has an outlet 1260 whichcan be coupled to an external valve 1261. The valve 1261 can be used tocontrol an external connection 1262 to the air compression cavity, suchas for coupling to a vacuum assembly or to a compressor assembly.

In FIG. 12B, a tire mold segment 1211 can have an air compression cavity1241 having close ends 1271 and 1281. The air compression cavity 1241can also has an outlet 1263 which can be coupled to an external valve1261. The valve 1261 can be used to control an external connection 1262to the air compression cavity, such as for coupling to a vacuum assemblyor to a compressor assembly.

In FIG. 12C, a tire mold segment 1212 can have an air compression cavity1242 having close ends 1272 and 1282. The air compression cavity 1242can also has an outlet 1264 which can be coupled to an external valve1265. The valve 1265 can be an one-way valve, allowing an externalsource, such as a compressor assembly delivering pressured air, to becoupled to the air compression cavity, while preventing air in the tiremold from leaving the air compression cavity.

FIGS. 13A-13B illustrate complete tire mold configurations according tosome embodiments. In FIG. 13A, a complete tire mold 1300 can includemultiple tire mold segments 1310. The tire mold segment 1310 can haveair compression cavities 1340 having close ends 1370 and 1380. Thus,each tire mold segment can have close air compression cavities. In FIG.13B, a complete tire mold 1301 can include multiple tire mold segments1311. The tire mold segment 1311 can have air compression cavities 1351having open ends, together with a middle opening, which can be coupledto a valve 1360. Thus, the air compression cavities can be connectedtogether, and one valve can be used a complete circumferential aircompression cavity that includes multiple air compression cavities fromthe mold segments. In some embodiments, the air compression cavities canbe cross linked, so that one valve can be used for multiplecircumferential air compression cavities. A vacuum assembly 1367 and/ora cylinder of pressurized fluid 1365 (e.g., compressed gas) can becoupled to the valve 1360, for example, to control the pressure of theair compression cavity 1341 or to clean the air compression cavity 1341.

Other configurations can be used, for example, tire mold segments havingtwo close ends, an open end and a close end, or a mismatch of differentconfigurations of tire mold segments.

The tire mold can be used for curing rubber materials for making a tire,with the air compression cavity assisting in preventing irregularitiesin the cured tire surface that can have the shape of the respective airbubble in the tire and in preventing the rubber materials from enteringthe surface connection slots in the tire mold.

Multiple tire segments can be assembled to form a complete tire mold,which includes a complete circumferential mold for making a round tire.The complete tire mold is open, e.g., the tire mold segments are placedapart for each other. A green tire can be placed in the open tire mold.The green tire can be a tire without the tire tread, e.g., a tire thatis formed by mechanically assembling layers of rubber materials aroundreinforced meshes. The tire mold then can be closed, e.g., the tire moldsegments are pushed against each other to form a completecircumferential mold around the green tire.

The green tire can be heated and pressurized to get the tread pattern onthe tire mold to be transferred to the tire surface. The air in the tiremold will be evacuated during the expansion of the green tire to themold tread surface, which will push the air to the surface connectionslots, e.g., the slots that are connected to the air compression cavity.

In some embodiments, to assist in the evacuation of the air in the tiremold, in a beginning stage, the air compression cavity can be coupled toa vacuum assembly, for example, through a valve connected to the aircompression cavity. The valve can be close after a period of time. Thepressure in the air compression cavity can be sub-atmospheric, such asbelow 0.9 or below 0.5 atmospheric pressure.

In some embodiments, the vacuum assembly can stop after an initial time,e.g., the valve connecting to the air compression cavity can be closedafter the initial time. Alternatively, the vacuum assembly does notstart at all, or the valve is always closed. The evacuation of the airinside the tire mold can occur only due to the pushing of the green tiretoward the tread pattern of the tire mold. Since the air compressioncavity is isolated from the outside ambient, the pressure in the aircompression cavity can increase during the expansion of the green tire.The more the green tire approaches the tread pattern, the more the airwill be evacuated to the air compression cavity, and the higher thepressure in the air compression cavity becomes. The pressure in the aircompression cavity can exert a counter pressure to the green tire, thuscan limit the entrance of rubber and rubber debris into the surfaceconnection slots.

In some embodiments, to assist in preventing the entrance of rubber andrubber debris to the surface connection slots, the air compressioncavity can be coupled to a gas source, such as a pressurized cylinder ora compressor, for example, through a valve connected to the aircompression cavity. The valve can be close after a period of time. Thepressure in the air compression cavity can be regulated to optimize theblockage of rubber and rubber debris to the surface connection slots.The pressure of the air generated from the gas source can be higher thanatmospheric pressure, such as between 1 and 2 bar pressure.

In some embodiments, the application of the vacuum assembly and the gassource can be controlled to optimize the tire curing process. During abeginning stage of the expansion of the green tire, e.g., when the greentire starts to expand, a low pressure can be applied to the aircompression cavity, for example, by the vacuum assembly, to assist indisplacement of air from the mold into a compression cavity. During anend stage of the expansion of the green tire, e.g., when the green tirehas reached the tread pattern surface of the tire mold, a high pressurecan be applied to the air compression cavity, for example, by the gassource, to assist in preventing the rubber or rubber debris fromcontaminating the surface connection slots, e.g., entering the surfaceconnection slots and blocking the air evacuation pathway.

The tire can be cured, for example, by heating the tire mold. After thecuring is completed, the tire mold can be open, e.g., the tire moldsegments can be separated from each other, and the cured tire can beremoved from the tire mold.

In some embodiments, after the curing process is completed, and beforeor during the opening of the tire mold, a gas source can be coupled tothe air compression cavity. Air can travel from the gas source to theair compression cavity, to the surface connection slots. A layer of aircan be formed between the mold and the cured tire. The layer of air canfacilitate the de-molding process, e.g., reducing the adhesion of thecured tire to the tire mold. The pressure in the air compression cavitycan be regulated to optimize the air layer formation. The pressure ofthe air generated from the gas source can be higher than atmosphericpressure, such as between 1 and 10 bar pressure, or between 2 and 5 bar.

In some embodiments, the gas source can continue blowing air through theair compression cavity and the surface connection slots for cleaning thesurface connection slots. The pressure of the air generated from the gassource can be higher than atmospheric pressure, such as between 1 and 10bar pressure, between 5 and 10 bar, or between 2 and 5 bar. The processcan be continued with a new green tire.

FIG. 14 illustrates a flow chart for forming a tire mold or a tire moldsegment according to some embodiments. The tire mold segment can have anair compression cavity connected to multiple surface connection slots,thus reducing the number of back side cavities. The air compressioncavity can be embedded in the tire mold segment body, thus can increasethe structural integrity of the tire mold segment. The air compressioncavity can have structural supports, for example, pillars or walls.

Operation 1400 provides a tire mold body, such as a tire mold segmentbody. The tire mold body can have multiple tread blocks. Operation 1410forms an air compression cavity inside the tire mold body, wherein theair compression cavity is configured to run across the multiple treadblocks, wherein the air compression cavity is configured to form anangle with multiple sipes in the multiple tread blocks. Operation 1420forms multiple surface connection slots in the multiple tread blocks,wherein the surface connection slots are separated by the sipes, whereinthe surface connection slots are connected to the air compressioncavity.

In some embodiments, the present invention discloses methods to formtire molds or tire mold segments, and tire molds or tire mold segmentsgenerated from the methods, that include air compression cavities thatcan be connected to multiple surface connection slots of the tire molds.The air compression cavities can be embedded in the tire mold, and canbe isolated from the outside ambient. In some embodiments, the aircompression cavities can be open to the outside ambient. The opened aircompression cavities can allow accesses to the multiple surfaceconnection slots, for example, so that compressed gas, liquid, orgas/liquid mixture can be used to clean the surface connection slotsfrom inside out. The opened air compression cavities can be closed,e.g., isolated from the outside ambient, by a valve assembly. The valveassembly can include an one way valve, for example, to pressurizing thecavities.

The methods to form tire molds or tire mold segments can include castprocesses, milling processes, or additive manufacturing processes toform the tire molds or tire mold segments. A negative mold body can beformed, including a surface having a tread pattern. The negative moldbody can be cast, using melted aluminum (or another suitable metalalloy) to be poured around a positive model of the tire tread surface.In direct milling, a negative tread pattern can be directly milled into,for example, an aluminum or steel segment body. In some embodiments, thetire mold segment can include multiple portions, such as a support bodyportion with a separate tread pattern portion. The support body portioncan be milled or cast. The tread pattern portion can be inserted intothe support body portion as a separate layer. The tread pattern portioncan be made by, for example, direct milling, casting or alternatively byadditive manufacturing technologies such as 3D printing, or selectivelaser melting.

One or more compression cavities can then be formed in the negative moldbody. The compression cavities can be prepared so that the compressioncavities can be formed together with the negative mold body. Forexample, in cases of a cast mold, the compression cavities can begenerated by inserting a suitable cavity such as a tube or a profile ontop of the model prior to the casting process. Alternatively a lost corecan be used. A conduit can be formed in the mold body after the curingprocess, which can function as the compression cavity.

The compression cavities can also be formed after forming the negativemold body. For example, in cases of a milled mold, the compressioncavities can be generated by milling an open cavity along a side of themold body. In cases of a mold body having multiple portions, thecompression cavity can be created by either milling an open cavity onthe rear side of the tread pattern portion, and/or by milling an opencavity in the support body portion. A compression cavity can be formedafter mounting the tread pattern portion onto the support body portion.

In some embodiments, the volume of the compression cavity can be adaptedto the air volume that is displaced by the tire size cured in the mold.For example, the compression volume can be directly proportional to theair volume inside the closed tire mold, to build up a slight counterpressure in the compression cavity to limit rubber from possiblyentering into the surface connection slots.

Surface connection slots can then be made to connect the compressioncavities to the tread surface. The connection slot can be as narrow aspossible, for example between 10-300 microns. This is for exampleachieved by using a liquid-jet laser process as described in U.S. Pat.No. 8,859,988, which is hereby incorporated by reference in itsentirety. Similar to a mechanical milling process, the liquid-jet laserpasses over the tread surface multiple times and removes material witheach pass. This process is repeated until there is a fluid connectionbetween the tread surface and the compression cavity. Preferentially theconnecting slot is oriented in a near parallel direction to the sipes(lamellas) or other features inside the tread block. Such orientationcan be useful to connect an as large as possible area in the tread blockto the compression cavity. At the same time, such near parallelconnection slot allows easy implementation in complex treads such as isthe case for winter tires or rain tires. In such cases the sipe densityis high and the sipe spacing is narrow.

FIGS. 15A-15E illustrate a process for forming a tire mold segmentaccording to some embodiments. A cast process can have an aircompression cavity embedded in a cast mold before a casting material ispoured to the cast mold to form the tire mold or tire mold segment. Alost core casting process can be used, in which a sacrificial materialis used, and then being removed to form an air compression cavity. Ahollow element can be placed in the cast mold to form the aircompression cavity.

FIG. 15A shows a tire tread model mold 1500, which includes a positivetread pattern of a tire. The positive tread pattern shows the treadpattern that is similar to the tread pattern on a tire. For example, thepositive tread pattern can include multiple tread blocks 1550, which aresimilar to the tread blocks on a tire. A difference between the tiretread model mold 1500 and a tire is the sipes 1530. The tire tread modelmold 1500 can have the sipes 1530 inserted in an invert position, sothat when the sipes 1530 are removed from the tire tread model mold 1500during the casting process, a pattern of a tire can be shown. Thus thetire does not have the sipes 1530, only the indentation or image thatthe sipes 1530 form.

In FIG. 15B, an element 1540 is coupled to the tire tread model mold1500, for example, attached to the sipes 1530. The element 1540 isconfigured to form an air compression cavity in a tire mold segment. Forexample, the element 1540 can include a sacrificial material, such as alost core material that can be removed after a casting process iscompleted. A water soluble, salt based material, such as salt or a saltcompound, can be used as a lost core material. The removal of thesacrificial material can leave a void, which can function as an aircompression cavity.

In FIG. 15C, a cast material 1510, such as aluminum or a metal alloy,can fill the tire tread model mold, covering the element 1540 and thesipes 1530. In FIG. 15D, the tire tread model mold can be removed. Theelement 1540 can form an air compression cavity 1545.

In FIG. 15E, surface connection slots 1520 can be formed, connecting thetread pattern of the mold segment to the air compression cavity 1545.For example, the tread pattern can include tread structure 1565, whichcan trap air during the vulcanization process, resulting in voids ordefects in the rubber tire. By providing surface connection slots 1520,e.g., connecting the cavity 1565 to the air compression cavity 1545,trapped air can escape the cavity 1565 into the air compression cavity1545. The air compression cavity 1545 can be configured to connect tomultiple surface connection slots 1520, e.g., the air compression cavity1545 can run at an angle with the cavities 1565, allowing multiplesurface connection slots to intersect the air compression cavity 1545.

Different configurations for the formation of the air compression cavitycan be used, instead of a lost core process. For example, a hollowelement, such as a hollow tube, can be used, with the volume inside thehollow element served as the air compression cavity.

FIGS. 16A-16C illustrate a process for forming a tire mold segmentaccording to some embodiments. The air compression cavity can be formedby using a hollow element, such as a hollow tube. The hollow volume ofthe hollow tube can function as an air compression cavity.

FIG. 16A shows a tire tread model mold 1600, which includes a positivetread pattern of a tire, including multiple tread blocks 1650 and sipes1630. A hollow element 1640 is coupled to the tire tread model mold1600, for example, attached to the sipes 1630 or to a spacer so that theelement 1640 will be embedded inside the tire mold segment. The hollowvolume of the hollow element can act as an air compression cavity. Forexample, the hollow element 1640 can include a hollow tube or conduit,having a wall surrounding an empty volume. A casting material, such asaluminum or a metal alloy, can fill the tire tread model mold, coveringthe outside of the hollow element 1640. After the tire tread model moldis removed, the volume inside the hollow element 1640 can form an aircompression cavity.

In FIG. 16B, a cast material 1610, such as aluminum or a metal alloy,can fill the tire tread model mold, covering the hollow element 1640 andthe sipes 1630. Surface connection slots 1620 can be formed, cuttingthrough the cast material 1610. In FIG. 16C, the surface connectionslots can be cut through the wall of the hollow element 1640, to connectto the air compression cavity 1635. For example, the tread pattern caninclude tread structure 1665, in which air can escape the treadstructure 1665 into the air compression cavity 1640 through the surfaceconnection slots 1620.

FIG. 17 illustrates a flow chart for forming a tire mold or a tire moldsegment having an air compression cavity according to some embodiments.Operation 1700 provides a tire tread model mold, wherein the tire treadmodel mold comprises a positive tread pattern of a tire. The tire treadmodel mold can be made from a ceramic material, for example, to castaluminum molds or other metallic molds. Other elements can be includedin the tire tread model mold, such as sipes.

Operation 1710 attaches an element along a first surface of the tiretread model mold, wherein the element is spaced apart from the firstsurface, wherein the element comprises a hollow element or a sacrificialelement, wherein the element is configured to form an air compressioncavity. Operation 1720 casts a negative mold using the tire tread modelmold, wherein the cast negative mold comprises the element and a mirrorimage of the positive tread pattern on a second surface of the negativemold. Operation 1730 forms connection elements from the second surfaceto the hollow portion of the element, wherein a dimension of theconnection elements is between 10 and 300 microns.

In some embodiments, the air compression cavity can be formed with aconstant and minimum separation distance from the tread surface. Theshort separation distance between the air compression cavity and thetread surface can allow a quick formation of the surface connectionslots, e.g., the depth of the surface connection slots is the same asthe separation distance between the tread surface and an inner surfaceof the air compression cavity. In some embodiments, the surfaceconnection slots can be slightly deeper to ensure a safe connection andin particular a large enough contact surface in case of a round orcylindrical compression cavity.

In some embodiments, the air compression cavity is configured so thatthe separation distance has a minimum variation, e.g., the standarddeviation of the separation distance is smallest. Spacers can be used tospace the air compression cavity, for example, to control the separationdistance. In some embodiments, the sipes can be configured to functionas spacers.

FIGS. 18A-18F illustrate configurations for forming an air compressioncavity according to some embodiments. In FIG. 18A, a hollow element 1840is coupled to the tire tread model mold 1800, for example, attached tosipes 1830 so that the hollow element 1840 will be embedded inside thetire mold segment. The hollow portion of the hollow element 1840 isconfigured to form an air compression cavity in a tire mold segment.FIGS. 18B and 18C show different configurations, using a cross sectionview F-F′. In FIG. 18B, a sipe 1831 can have a cut in the exposedportion, wherein such exposed portion can be used to affix the sipe intothe cast mold. The cut can be mated with the outside circumference ofthe hollow element 1841. Thus the distance 1871 from the hollow element1841 to the outside surface of the tire mold can be controlled. Thisdistance 1871 can be the length of the surface connection slots, e.g.,the distance that a cut will need to be made to connect the surface ofthe tire mold to the air compression cavity. FIG. 18C shows a differenthollow element 1842, which is attached to sipe 1832 with a differentconfiguration.

In FIG. 18D, a hollow element 1845 is coupled to the tire tread modelmold 1805, for example, attached to spacers 1885 so that the hollowelement 1845 will be embedded inside the tire mold segment. The hollowportion of the hollow element 1845 is configured to form an aircompression cavity in a tire mold segment. FIGS. 18E and 18F showdifferent configurations, using a cross section view G-G′. A spacer 1886can be used to space the hollow element 1846 from the outside surface ofthe tire mold. Thus the distance 1876 from the hollow element 1846 tothe outside surface of the tire mold can be controlled. This distance1876 can be the length of the surface connection slots, e.g., thedistance that a cut will need to be made to connect the surface of thetire mold to the air compression cavity.

In some embodiments, a milling process can be used to form the aircompression cavity. After a tread pattern body is formed, sipes 1835 canbe attached, and air compression cavities can be prepared before formingthe surface connection slots.

FIGS. 19A-19D illustrate a process for forming an air compression cavityaccording to some embodiments. In FIG. 19A, a tread pattern body 1900can be formed, for example, by milling a block of metal such as aluminumor an metal alloy. The milling process can form tread blocks 1950 on asurface of the tread pattern body 1900. In FIG. 19B, air compressioncavities 1940 can be formed in the tread block body 1900, such as bymilling or drilling through the body 1900. As shown, the air compressioncavities can be formed along a thickness of the tire. Alternatively, theair compression cavities can be formed along a circumferential directionof the tire, e.g., making an angle with the direction of the thicknessof the tire.

In FIG. 19C, sipes 1930 can be attached to the surfaces of the treadblocks, for example by making sipe insertion slots using a liquid-jetlaser. In FIG. 19D, surface connection slots 1920 can be formed, forexample, by a liquid jet guided laser system, to connect a surface ofthe tread blocks to the air compression cavity 1940. In someembodiments, the sipe insertion slots and the surface connection slotscan be formed by a same liquid jet guided laser system.

FIG. 20 illustrates a flow chart for forming a tire mold or a tire moldsegment according to some embodiments. Operation 2000 forms a tire moldbody, wherein the tire mold body comprises a tread pattern of a tire.The tire mold body can be formed by a milling process. Operation 2010attaches sipes on the tread pattern. Operation 2020 forms an aircompression cavity in the tire mold body, wherein the air compressioncavity runs at an angle with a direction of the sipes. The aircompression cavity can be formed by a milling process. In someembodiments, the air compression cavity can be formed before attachingthe sipes. In this way, the liquid-jet laser can make the connectionslots and sipe slots in one effort, also the mechanical stability of theinserted sipes can be improved without post-drilling or milling a largecavity.

Operation 2030 forms surface connection slots from the tread pattern tothe air compression cavity, wherein a dimension of the surfaceconnection slots is between 10 and 300 microns

In some embodiments, the present invention discloses multiple-stepmethods to form tire molds or tire mold segments, and multiple-part tiremolds or tire mold segments generated from the methods, that includeforming at least a mold support and a mold insert. A mold support can beformed, for example, by casting or by milling, as a support for the moldinsert. A mold insert can be formed, by casting, milling, or by anadditive manufacturing process, which can include tire tread pattern andair compression cavities.

With the two part tire mold, the air compression cavity can be preparedat an exposed surface of either the mold insert or the mold support,such as at a back side of the mold insert, instead of being embeddedinside the tire mold. Thus the air compression cavity can be formed bymilling, casting or additive manufacturing.

FIGS. 21A-21C illustrate a two-part tire mold segment according to someembodiments. A mold insert 2160 can be formed, having a tread pattern ata top surface, and air compression cavities 2140 at an opposite backsurface. The tread pattern can include multiple tread blocks 2150, whichare separated by sidewalls 2155. Sipes 2130 can be included in the moldinsert. Surface connection slots 2120 can also be formed in the moldinsert, connecting the top surface of the tread pattern to the backsurface of the cavities 2140.

The air compression cavities can be open cavities, e.g., having exposedcavities to the outside ambient. The mold insert 2160 can be attached toa mold support 2110. The mold support 2110 can supply other sides forthe air compression cavities to form closed air compression cavities, orto form air compression cavities with outlets to the outside ambient.The air compression cavities can run along multiple tread blocks,intersecting multiple surface connection slots.

In some embodiments, the mold insert 2160 can be formed by an additivemanufacturing process, such as 3D printing or stereo lithography,including the tread pattern and the air compression cavity.

FIGS. 22A-22B illustrate different configurations for two part moldsaccording to some embodiments. A two part mold can include a mold insertattached to a mold support. The mold insert can include an exposed treadpattern surface, for making tread blocks in a tire. The mold support canbe configured to support the mold insert.

In FIG. 22A, a mold insert 2260 can have a tread pattern includingmultiple tread blocks 2250 on a front side. A back side can be flat,thus the mold insert can be formed with one treated surface. A moldsupport 2210 can have recesses 2240 on a top surface, which, after themold insert is coupled with the mold support, can form the aircompression cavities.

In FIG. 22B, a mold insert 2265 can have a tread pattern includingmultiple tread blocks 2255 on a front side. Recesses 2242 can also beformed on a back side. A mold support 2215 can have recesses 2245 on atop surface, which, after the mold insert is coupled with the moldsupport, can form the air compression cavities together with therecesses 2242 from the mold insert.

In some embodiments, other configurations can be used, such as more thantwo part molds, e.g., a mold support and multiple mold insert portions,or multiple mold support portions and one or more mold insert portions.

FIG. 23 illustrates a flow chart for forming a tire mold according tosome embodiments. Operation 2300 forms a tire mold support. Operation2310 forms a tire mold insert. The tire mold insert can be configured tocouple to the tire mold support. The tire mold insert can comprise atleast a recess, which can function as an air compression cavity whencoupled with the mold support. The tire mold insert can be formed by anadditive manufacturing process, such as 3D printing. The tire moldinsert can be formed by a milling or casting process. Operation 2320forms sipes in the tire mold insert. Operation 2330 forms surfaceconnection slots connecting a surface of the tire mold insert to the aircompression cavity. The tire mold insert can be coupled to the tire moldsupport. Operation 2340 assembles the tire mold insert with the tiremold support.

In some embodiments, the present invention discloses methods and systemsusing liquid jet guided laser technology. A laser beam can be internallyreflected within a liquid jet, thus providing a parallel laser beam formaterial processing, such as material cutting.

In some embodiments, the present invention discloses using a liquid jetguided laser system for forming the surface connection slots in a tiremold. The liquid jet guided laser system can form channels having linewidths between 10 and 300 microns, which can be suitable for selectiveremoval of air in a mold.

The length and width of the surface connection slots can be determinedby the distance that the laser beam travels. For example, the laser beamcan travel along a direction x to form a line having a length largerthan the dimension of the laser beam inside the liquid-jet. The surfaceconnection slot can have a width that is similar to the dimension of thelaser beam inside the liquid-jet, for example, by the laser beam makinga same path along the x direction.

Multiple passes can be performed to increase the depth of the surfaceconnection slots. The surface connection slot can be cut until connectedwith a cavity. The surface connection slot and the cavity can beconfigured so that they are fluidly connected after the formation of thesurface connection slot. The cavity can provide a thinner thickness ofthe object at the surface connection slot location, thus can reduce thedepth of the surface connection slot, since the surface connection slotonly needs to connect to the cavity instead of cutting through theobject.

The liquid jet guided laser system can generate surface connection slotshaving different sidewall profiles. A rotating mechanism can allow thelaser beam to cut through the material at different angles. For example,the laser beam can be perpendicular to the surface of the material,cutting through the material at a normal angle. The laser beam can forman angle with the normal direction of the material surface, cuttingthrough the material at an angle. In addition, the depth of the cut canbe controlled, for example, by running the laser beam at a slow speed orfor more iteration. Thus the sidewall of the angled cut can becontrolled through the depth of the laser cut.

An x-y mechanism can also be coupled to the liquid guided laser beam,which can move the laser beam in any directions to form the patterns.Together with the rotating mechanism, the laser beam can generatedifferent depth profile patterns, including inverse taper shaped cutpatterns (e.g., the opening at the surface of the material is largerthan the opening at the bottom of the laser cut), taper shaped cutpatterns (e.g., the opening at the surface of the material is smallerthan the opening at the bottom of the laser cut), and other sidewallprofiles. Multiple parameters of a liquid jet guided laser beam can bevaried to achieve a surface connection slot having a sidewall pattern.The parameters can include a linear speed, a rotating speed, a power,and a number of passes.

In some embodiments, the present invention discloses methods and systemsusing a liquid jet guided laser system for forming structures havingdifferent profiles. For example, the bottom of a structured cut by aliquid jet guided laser system can be flat. In addition, other patternscan be formed, such as a concave or convex bottom surface, which can begenerated, for example, by varying the speed of the laser beam, byvarying the angle of the laser beam toward the object surface, byvarying a power of the laser beam, or by varying a number of passesthrough the cut.

For example, a slow speed portion can generate a deeper cut portion, anda higher speed portion can generate a shallower cut portion.Alternatively, a higher power portion can generate a deeper cut portion,and a lower power portion can generate a shallower cut portion. Also,different number of passes can form different profiles. For example, toform a deeper cut, a higher number of passes can be made. At a topportion, the laser beam can run from one end to the opposite end. At anintermediate portion, the laser beam can run from one end to a middle ofthe cut length. Thus the opposite end can have a less number of passesthat the laser beam cutting through. At a bottom portion, the laser beamcan run a small middle portion, thus this middle portion can have ahighest number of laser passing through.

In some embodiments, the present invention discloses a liquid jet guidedlaser system for generating channels having different depth profiles. Anenergy modulator or a moving speed modulator can be coupled to the lasersystem to allow the laser beam to cut through the material at differentdepths. For example, a lower energy laser beam or a laser beam moving ata faster speed can form a channel having shallow depth while a higherenergy laser beam or a laser beam moving at a slow speed can form achannel having deeper depth. A continuous changing profile of speed orenergy can form a smooth depth profile.

In some embodiments, the present invention discloses methods and systemsusing liquid jet laser based processes to form surface connection slotsin a mold, such as a mold for making tires or a mold for making shoes.In liquid-jet guided laser technology, a laser beam is guided in aliquid jet flow through internal reflection. The laser beam and theliquid jet are coupled through a coupling unit, which includes a chamberfor accepting a liquid flow. The coupling unit can also include anozzle, which is attached to one end of the chamber, for directing theliquid flow to form a liquid jet. The coupling unit can also include alaser protection window, which can separate the dry environment of thelaser beam with the liquid environment of the liquid jet.

FIG. 24 illustrates a liquid jet guided laser system according to someembodiments. The liquid jet guided laser system 2400 can include achamber 2420, which is configured to guide a liquid flow 2422. Thechamber 2420 can have the shape of a disk, with an inlet at anperipheral portion to accept a liquid input. The chamber 2420 caninclude an opening for direct the liquid flow to form a liquid jet 2425.At one side of the chamber 2420 is a nozzle 2430, which includes anozzle stone. The nozzle 2430 can be used to control the size of theliquid jet 2425. The nozzle 2430 can be used to guide and protect theliquid jet.

The liquid jet guided laser system 2400 can include a protection window2470, which can form an opposite side of the chamber 2420. A laser beam2480 can be focused on the liquid jet 2425. The laser beam can beconfined in the liquid jet due to internal reflection. The liquid jetguided laser beam can be used to cut lines or holes in workpiece 2450.

FIGS. 25A-25B illustrate configurations of surface connection slot usinga liquid jet guided laser process according to some embodiments. In FIG.25A, an air compression cavity 2540 can be formed in a tire mold segment2510. The tire mold segment 2510 can also have a tread surface havingmultiple tread blocks 2550, separated by tread block side walls 2555. Aliquid jet guided laser beam 2570 can be used to cut surface connectionslots 2520. The surface connection slots 2520 can be cut across the aircompression cavity 2540, e.g., multiple surface connection slots 2520can be connected to an air compression cavity 2540.

In FIG. 25B, the air compression cavity 2545 can include a hollowelement, e.g., a hollow tube having a wall 2546. The material for thewall 2546 of the hollow element can be different from the material ofthe tire mold segment 2511. Thus different operating steps for theliquid jet guided laser beam can be used, for example, a first stepincluding first operating conditions 2571 to cut a first portion 2521 ofthe surface connection slot through the tire mold body, and a secondstep including second operating conditions 2572 to cut a second portion2522 through the wall of the hollow element.

In some embodiments, the air compression cavity and connection slot canbe made in one effort using the liquid-jet guided laser. The liquid-jetguided laser can form structures having depth and sidewall profiles thatare configured to optimize gas flow, such as air evacuation in a mold.For example, the channels can have shapes, e.g., sidewall and depthprofiles, that conform to the flow dynamic, including having minimum orreduced dead spaces or stagnant areas.

FIGS. 26A-26C illustrate configurations for air compression cavitiesaccording to some embodiments. In FIG. 26A, air compression cavity 2640in a tire mold segment 2610 can be formed by a liquid jet guided lasersystem 2670. The air compression cavity 2640 can have a small opening2620, which can function as a surface connection slot, e.g., having adimension between 10 and 300 microns. Thus the liquid jet guided lasersystem 2670 can form the air compression cavity 2640 and the surfaceconnection slot 2620 in one operation.

FIGS. 26B and 26C show different configurations for an one passformation of the air compression cavity and the surface connection slot.A laser system 2671/2672 can be operated to form an air compressioncavity 2641/2542 and a surface connection slot 2621/2622 in a tire moldsegment 2611/2612.

In some embodiments, the present invention discloses methods to formsurface connection slots, including an end point detection configurationfor a feed back control of the surface connection slot formation. Thesurface connection slots can be cut by a liquid jet guided laser system,which can require multiple passes to cut through the mold material, toconnect the outer surface of the mold with the air compression cavity. Asensor can be installed in a vicinity of the air compression cavity,which can detect when the laser cuts through the material. For example,the sensor can include a light detection sensor, and when the laser cutthrough the material, e.g., the cut surface connection slot has aconnection with the cavity, light, for example a laser light, can passthrough the surface connection slot to the cavity to reach the sensor.After the surface connection slot is cut through, for example,additional 2-5 passes can be performed to ensure the connection. Othersensors can be used, such as a sound sensor, which can detect a changein the sound, either amplitude or frequency, of the laser cut process.Pressure sensors can also be used for detecting pressure changes.

For a proper air evacuation from the mold during the tire curingprocess, it is important that the surface connection slots penetratefrom the surface successfully into the compression cavities. When makingsuch surface connection slots with a liquid-jet laser there are goodways for process control, for example by adding a sensor to an open endof the compression cavity during the laser process. Such sensor can bean optical, an acoustic or other type of sensor. In case of an opticalsensor the sensitivity of the sensor is matched to the wavelength of thelaser. In case the connection slot is not yet connected to thecompression cavity, the compression cavity is nearly dark. Once theconnection is successful, the liquid-jet laser will enter into thecavity and cause a bright laser light that will be detected easily besuch sensor.

Alternatively an acoustic sensor can be used. The compression cavity canfunction as an acoustic resonator. As soon as the liquid-jet laserconnects the surface of the mold to the compression cavity a strong tonecan be observed from the compression cavity.

Such sensor can be coupled to the CNC controls of the machine in whichthe liquid-jet laser is integrated. It could be set up as such thatafter detection of a successful connection of the mold surface to thecompression cavity, 1, 2, or 10 more buffer passes are made to have agood connection. Such closed-loop feedback allows to automatically reacton alloy impurities of the mold as well as distance differences of thecompression cavity to the surface.

FIGS. 27A-27C illustrate an end point detection for a surface connectionslot formation according to some embodiments. In FIG. 27A, a tire mold2710 has been prepared, including an air compression cavity 2740 andsipes 2730. The tire mold 2710 will need to have surface connectionslots 2720, which can connect the top surfaces 2760 of the tread blockswith the air compression cavity 2740.

In FIG. 27B, a sensor assembly 2780/2685 can be coupled to the aircompression cavity 2740. The sensor assembly 2780/2685 can include asensor 2780 and a blocking element 2785. The sensor assembly 2780/2685can include a sensor emitter 2780 and a sensor receiver 2785. The sensorassembly can include a photo sensor, for detecting a light change whenthe surface connection slots are cut through, for example, by a liquidjet guided laser system 2770. The sensor assembly can include anacoustic sensor, for detecting a sound change when the surfaceconnection slots are cut through. The sensor assembly can include apressure sensor, for detecting a pressure change when the surfaceconnection slots are cut through.

FIG. 27C shows a signal detection curve, showing detected signals as afunction of passes that the laser beam cuts through the mold material.In the beginning, when the laser cuts the surface connection slots, butnot connected to the air compression cavity, the signal 2790 can be low.For example, a first sound (amplitude or pitch) 2790 can be detected.When the laser cuts through the mold material, e.g., the surfaceconnection slots are connected to the air compression cavity, the signalchanges, signifying a different in the cut process. For example, asecond sound (amplitude or pitch) 2795 can be detected. The change inthe detected signal can show a difference in the cut process, implyingthat the surface connection slots have been cut through. The laser cutprocess can stop, or laser cut process can proceed for a few morepasses, such as 1, 2, or 10 more passes, to ensure a complete cutthrough.

The sensor can provide an end point detection for the cut process, thuscan significantly reduce the required manufacturing time of the lasercut process.

FIG. 28 illustrates a flow chart for a tire mold formation processaccording to some embodiments. After forming the mold body, includingtread patterns and sipes, surface connection slots can be cut, through acut process having end point detection using sensor. Operation 2800installs a sensor in an air compression cavity. Operation 2810 cuts asurface connection slot to connect a surface to the air compressioncavity. Operation 2820 monitors a signal from the sensor. Operation 2830stops the cutting process when the signal reaches a set point. A fewmore passes can be used after the signal reaches the set point.

In some embodiments, the present invention discloses cleaning methodsfor cleaning tire molds, using an air compression cavity. A tire moldsection, in particular the surface connection slots, can getcontaminated with rubber or debris. The tire mold sections will need tobe cleaned to remove the rubber or debris contaminants. A mechanical orthermal impact cleaning process, such as CO₂ cleaning, or selectivelaser cleaning only effectively reach the surface of the tire mold andcannot reach and clean inside venting structures, e.g., surfaceconnection slots. Due to this fact, for example puzzle molds stillrequire disassembly for periodic cleaning, to remove any rubber debrisfrom the surface connection slots.

In some embodiments, the present invention discloses methods to cleanthe surface connection slots in a tire mold, using a pressurized fluid,such as a compressed gas, a pressurized liquid, or a compressedgas-liquid mixture. The pressurized fluid can be coupled to an aircompression cavity. The pressurized fluid can enter and pass through thesurface connection slots, effectively cleaning the surface connectionslots from inside out, removing any debris in the surface connectionslots. Since the air compression cavity can be connected to multiplesurface connection slots, such as hundreds of surface connection slots,a small number of air compression cavities can be included in a tiremold. Thus, by connecting a pressurized fluid to the air compressioncavities, the tire mold segment or the surface connection slots can becleaned.

In some embodiments, the cleaning process can be also applicable formicro-holes or spring vents. An air compression cavity can be connectedto by micro holes or by spring vents. A compression fluid can then becoupled to the air compression cavity to clean the micro holes or thespring vents from the inside out, removing any debris in the micro holesor the spring vents.

In some embodiments, the tire mold can be cleaned after performing aliquid-jet laser operation to connect the tread surface to a compressioncavity. Such operation can be useful to prepare the mold for example fora subsequent coating process (for example applying an anti-stickingcoating). The tire mold can also be cleaned after using the mold forcuring a tire. Such operation can be performed after each tire that iscured. The tire mold can also be cleaned as a preventive maintenance ofthe mold. Such operation can be performed regularly after, for example,1000, 2000 or 6000 curing cycles.

The cleaning process can include blowing a pressurized fluid from theair compression cavity to the surface connection slots. The cleaningprocess can be optimized for different mold operations. For example,after performing a liquid-jet laser operation, the cleaning process caninclude a liquid to remove debris generated from the mold fabricationprocess. A pressure tube can be connected to the compression cavity. Aliquid or gas can be inserted at high pressure to flush and remove anydebris from the compression cavity from the inside out. After this wetprocess the cavities can be dried by connecting CDA (Clean Dry Air) tothe same compression cavity. In both cases it can be needed to close theopposite side of the compression cavity with for example a cap orgasket.

After using the mold for curing a tire, the cleaning process can includeapplying a pressurized air to the compression cavity to “blow” debrisoutside of the compression cavity and from the surface connection slotsthat connect such cavity to the tread surface. It can be needed to closeone side of the compression cavity with for example a cap or gasket. Forpreventive maintenance of the mold, a pressure tube can be connected tothe compression cavity. A liquid or gas can be inserted at high pressureto flush and remove any debris from the compression cavity from theinside out. For example alcohol or a rubber solvent can be used. Afterthis wet process the cavities can be dried by connecting CDA (Clean DryAir) to the same compression cavity. In both cases it can be needed toclose the opposite side of the compression cavity with for example a capor gasket.

In some embodiments, for debris that are firmly stuck inside a surfaceconnection slot, a remedy can be to put such mold segment on aliquid-jet laser CNC machine and to open such channel by applying onlyliquid-pressure (i.e. 60-500 bar) or also to apply some laser energy to“melt” the debris and flush them away. Such step can apply duringpreventive maintenance to remove any metallic or rubber debris caused bythe tire curing process.

FIGS. 29A-29C illustrate a process for cleaning a tire mold segmentafter formation according to some embodiments. In FIG. 29A, a tire moldbody 2910 can be formed, including a tread surface having multiple treadblocks 2950, and multiple sipes 2930 installed in the tread blocks. Anair compression cavity 2940 can be embedded in the tire mold body. Theair compression cavity 2940 can have an outlet 2960, which can beconfigured to be connected to an external assembly, such as a vacuumassembly or a gas or liquid source.

In FIG. 29B, surface connection slots 2920 can be formed, connecting thetread surface with the air compression cavity 2940. The surfaceconnection slots can be formed by a liquid jet guided laser system 2925,which can cut through the material of the tire mold body with adimension suitable for air evacuation and prevent rubber material frompassing through, such as between 10 and 300 microns.

In FIG. 29C, a source 2970 can be coupled to the outlet 2960 of the aircompression cavity 2940 to clean the tire mold 2910. After the formationof the tire mold 2910, debris can be present, especially at the smallsurface connection slots, which can prevent the surface connection slotsfrom operating properly. A source 2970 can include a liquid source,which can provide a flow 2972 to the air compression cavity, cleaningthe tire mold and the surface connection slots. A source 2970 caninclude a gas source or a gas/liquid mixture source, which can provide aflow 2972 to the air compression cavity, cleaning the tire mold and thesurface connection slots, for example, by generating a gas flow 2975through the surface connection slots, pushing any debris outward.

FIG. 30 illustrates a flow chart for cleaning a tire mold after makingthe tire mold according to some embodiments. Operation 3000 provides atire mold body, wherein the tire mold body comprises a tread pattern ofa tire, wherein the tire mold body can optionally comprise multiplesipes, wherein the tire mold body comprises an air compression cavity.Operation 3010 forms surface connection slots from the tread pattern tothe air compression cavity, wherein a dimension of the surfaceconnection slots is between 10 and 300 microns. Operation 3020 suppliesa pressurized fluid to the air compression cavity, wherein thepressurized fluid escapes the surface connection slots for cleaning thetire mold.

FIGS. 31A-31C illustrate processes for cleaning a tire mold segmentaccording to some embodiments. In FIG. 31A, a tire mold segment 3110 isused for making a tire. The tire mold segment 3110 can have an aircompression cavity 3140, which is connected to multiple surfaceconnection slots 3120 in the tread pattern of the tire mold segment. Theair compression cavity 3140 can include a valve 3160 coupled to an inletof the air compression cavity. The valve can be close during the tireformation process, thus air in the tire mold can be compressed in theair compression cavity 3140.

During a tire making process, rubber material 3190 can be used, pressingon the tread pattern, and stopping at the surface connection slots. Theair in the tire mold segment can escape to the air compression cavity3140, preventing defect formation in the rubber tire.

In FIG. 31B, the valve 3160 can be open, connecting the air compressioncavity 3140 with a gas source 3170. The gas source 3170 can generate anair pressure 3172 in the air compression cavity 3140. The air pressure3172 can be controlled to lift the cured tire 3190 from the treadsurface of the tire mold. For example, the air source can be controlledto provide a pressure between 1 and 2 bar, which can reduce the adhesionof the cured tire to the tread surface, and then generate an air layer3171 under the cured tire. The air layer 3171 can assist in the removalof the cured tire.

In FIG. 31C, after one or more processes of making tires, the tire moldsegment might need to be cleaned, since rubber debris can be trapped tothe surface connection slots. The valve 3160 can be open, connecting theair compression cavity 3140 with the gas source 3170. The gas source3170 can generate an air flow 3173 to the air compression cavity 3140,and then escape the air compression cavity by the surface connectionslots 3120. The gas source can be controlled to provide a pressurebetween 1 and 10 bar, such as between 4 and 10 bar, which can force anytrapped debris to get out of the surface connection slots. The cleaningprocess can be performed after every tire making process, or after acertain number of tire curing cycles.

Other configurations can be used, such as a vacuum assembly can becoupled to the valve 3160 (with the valve opened) at the beginning ofthe tire making process (when the green tire expands to fill the treadpattern) to assist in displacement of air from the mold into acompression cavity. A gas source can be coupled to the valve 3160 (withthe valve opened) at the end of the time making process (after the greentire reaches the tread pattern) to assist in preventing the rubbermaterial from entering the surface connection slots. Hot gas source orpulsed gas source can be used.

FIGS. 32A-32D illustrate a process for post treatment a tire moldaccording to some embodiments. In FIG. 32A, a complete mold 3200,including multiple tire mold segments 3210, can be used to form a tire.The tire mold segments 3210 can be assembled to form the circumferentialmold 3200, enclosing a green tire 3201 in between. During the tirecuring process, air in the tire mold can escape to an air compressioncavity 3240, which has an outlet 3252 with a closed valve 3252A. Thusthe air in the tire mold is compressed in the air compression cavityduring the tire curing process.

In FIG. 32B, after the tire curing process is complete, a pressurizedfluid, such as a compressed air, can be applied to the outlet 3252 withan open valve 3252B. The compressed air can pressurize the aircompression cavity, which then can exert a force on the cured rubbertire 3202 through the surface connection slots. The pressurized air canform a layer of air 3257 at the interface of the rubber surface and thetire mold surface, effectively reducing or eliminating the adhesion ofthe rubber material to the tire mold surface.

In FIG. 32C, the tire mold segments 3210 can be released, for example,by expanding outward 3280. Valve 3252 can be closed 3252A. The curedrubber tire 3202 can be removed from the released tire moldconfiguration 3205. Since the adhesion between the tire 3202 and thetire mold segments 3210 can be significantly reduced by the air layer3257, the tire 3202 can be easily removed from the tire mold segments3210.

In FIG. 32D, the tire mold segments can be prepared to be cleaned.Coupling elements 3290 can be placed between the tire mold segments toconnect the air compression cavities between the tire mold segments. Forexample, a coupling element 3290 can have a conduit 3291 that connectsthe air compression cavity 3241 of the tire mold segment 3211 with theair compression cavity 3242 of the tire mold segment 3212. The couplingelements 3290 and the tire mold segments 3210 can form a complete aircircuit, allowing a pressurized fluid 3292 to enter the air compressioncavities for cleaning the surface connection slots of the tire moldsegments. For example, a pressurized fluid, such as a compressed air,can be applied to the open valve 3252B, pressurizing the air compressioncavities, and released 3295 through the surface connection slots toclean the tire mold, especially cleaning the surface connection slots.

Other configurations can be used. For example, the coupling elements caninclude an outlet for connecting to a source of pressurized fluid. Thuseach coupling elements can be used to clean two adjacent tire moldsegments.

FIG. 33 illustrates a flow chart for cleaning a tire mold according tosome embodiments. Operation 3300 forms a tire using a tire mold, whereinthe tire mold comprises an air compression cavity. Operation 3310removes the formed tire. Operation 3320 applies a pressurized fluid tothe air compression cavity.

In some embodiments, the tire mold can include multiple tire moldsegments that are assembled together to form a tire. After the tire isformed, the tire mold segments can be disassembled, for example, to takeout the tire. The tire mold segments can be re-assembled, and apressurized fluid can be applied to the air compression cavity to cleanthe surface connection slots.

What is claimed is:
 1. A method for making a tire mold with at least onetire mold segment, the method comprising: forming the tire mold segmentwith at least one part, wherein at least: one part is formed consistingof at least one mold insert, wherein: the mold insert includes a tiretread pattern at a top surface, the mold insert includes at least onesurface connection slot, wherein the surface connection slot is formedas an opening through the mold insert body, to connect the mold inserttop surface and back surface; one part is formed consisting of at leastone mold support, wherein: the mold support forms the body of the moldsegment; configuring the parts such that: the mold insert is attached tothe mold support to form the tire mold segment; configuring the at leasttwo tire mold segments to be adjacently closed to form a mold for makingtires; forming the mold insert with at least one air compression cavityat the opposite back surface; forming multiple connection slots toconnect the front surface with the air compression cavity; forming thecompression cavities such that they are physically separated from thetop surface; forming the compression cavities such that the compressioncavities are isolated from the outside ambient during the tire makingprocess; forming the connection slots such that the dimension of thesurface connection slots are configured to allow air to pass through,and prevent rubber material from entering.
 2. A method as in claim 1,wherein: the tire mold segment is a two-part tire mold segment.
 3. Amethod as in claim 1, wherein: multiple mold inserts are attached to therespective mold support.
 4. A method as in claim 1, wherein: at least apart of the mold segments are formed by an additive manufacturingprocess, wherein: the mold inserts are made by an additive manufacturingmethod.
 5. A method as in claim 4, wherein: the additive manufacturingprocess is 3D-printing.
 6. A method as in claim 1, wherein: the treadpattern of the mold insert includes multiple tread blocks which areseparated by side walls.
 7. A method as in claim 1, wherein: the treadpattern of the mold insert includes sipes.
 8. A method as in claim 1,wherein: the surface connection slots are of any shape having dimensionsbetween 10 and 300 microns.
 9. A method as in claim 1, wherein: thesurface connection slots and/or air compression cavity are formed by aliquid-jet guided laser.
 10. A method as in claim 1, wherein: thecompression cavity is of any shape having dimensions between 1 and 10mm.
 11. A method as in claim 1, wherein: the connection slots and/or aircompression cavity are formed after completion of the mold insert.
 12. Amethod as in claim 1, wherein: the mold support is formed by casting ormilling.
 13. A method as in claim 1, wherein: either the mold support isformed with recesses on a top surface or the mold insert is formed withrecesses on a bottom surface, which, after the mold insert is coupledwith the mold support, respectively forms an air compression cavity,wherein the recess forms a cavity between the back surface of the moldinsert and top surface of the mold support, and wherein the connectionslots formed in the mold inserts align with the recesses.
 14. A methodas in claim 1, wherein: The at least one mold insert can be replaced orinterchanged from the mold support.
 15. A tire mold comprising of atleast one tire mold segment, wherein: the tire mold segment ismultiple-parts, wherein: one part consists of at least one mold insert,wherein: the mold insert includes a tire tread pattern at a top surface,the mold insert includes at least one surface connection slot, whereinthe surface connection slot connects the mold insert top surface andback surface; one part consists of at least one mold support, wherein:the mold support forms the body of the mold segment; the parts areconfigured such that: the mold insert is attached to the mold support toform the tire mold segment, the at least two tire mold segmentsadjacently connect to form a mold for making tires; the mold insert isconfigured with at least one air compression cavity at the opposite backsurface; the multiple connection slots connect the front surface withthe air compression cavities; the compression cavities are configuredsuch that they are physically separated from the top surface; thecompression cavities are isolated from the outside ambient during thetire making process; the connection slots are configured such that thedimension of the surface connection slots allow air to pass through, andprevent rubber material from entering.
 16. A tire mold as in claim 15,wherein: at least a part of the mold segments are formed by an additivemanufacturing process.
 17. A tire mold as in claim 15, wherein: the moldsupport has recesses on a top surface, which, after the mold insert iscoupled with the mold support, forms an air compression cavity, whereinthe recess forms a cavity between the back surface of the mold insertand top surface of the mold support.
 18. A tire mold as in claim 16,wherein: the additive manufacturing process is 3D printing.